Following my request for the PostScript Printer Application I also request auto-connection for the same interfaces for my further 3 Printer Applications and ipp-usb:
The names in the Snap Store are “ghostscript-printer-app”, “hplip-printer-app”, “gutenprint-printer-app”, “ipp-usb”.
These interfaces are:
avahi-control: For registering the printers in Avahi, so that they DNS-SD-advertise themselves, like physical IPP network printers
raw-usb: To support printers connected to USB
hardware-observe: To observe the appearing of USB printers via UDEV to automatically load firmware files onto them (some need their firmware loaded everytime when they get turned on) in the Printer Applications and to automatically start the daemon in ipp-usb.